DELRAY BEACH, Fla. -- Juan Martin del Potro was stuck with too much idle time the past two seasons, limited to 14 matches in that span because of a series of wrist injuries.
So when the 2009 US Open champion was asked about his second-round opponent in the Delray Beach Open, del Potro shrugged his shoulders and deadpanned: "I don't know him. For two years I was at home, watching `The Simpsons."
It was quite a night for the 27-year-old del Potro, who beat American Denis Kudla 6-1, 6-4 on Tuesday in his first ATP match in 11 months.
Del Potro's win was a relief to tournament organizers after the top two seeds each had a quick exit. Kevin Anderson, the No. 1 seed and 2012 champion, was forced to retire from his match against Austin Krajicek due to a right shoulder injury. Hours later, second-seeded Bernard Tomic of Australia lost to American Rajeev Ram, 7-6 (3), 6-1.
The 27-year-old del Potro played just four matches last year and 10 in 2014. He has faced four surgeries -- one on his right wrist and three on his left -- since defeating Roger Federer for his only major title.
Once ranked in the top 10, del Potro is down to No. 1,041.
Against Kudla, he was surprisingly consistent, losing just 10 points on his serve in the match -- five of them on double faults. Rather than pound his once potent two-handed backhand, del Potro employed a new-found one-handed slice shot.
Del Potro next plays on Thursday against Australian John-Patrick Smith, a former All-American at the University of Tennessee.
Anderson had just dropped the first set to the 103rd-ranked American in a 7-3 tiebreaker when he sauntered to the sideline, packed his racket bag, shook his opponent's hand and walked off the court. Anderson also pulled out of the first tournament of the year in Chennai and retired from his opening match at the Australian Open last month due to a left-knee injury.
Krajicek was one of seven Americans to advance to the second round. Donald Young, a finalist last year, moved on when Mikhail Kukushkin of Kazakhstan retired with a leg injury while trailing 7-6 (3), 3-0. Sixth-seeded Steve Johnson squeaked past Australian John Millman 6-3, 5-7, 7-6 (10-8), and Sam Querrey defeated Thiemo de Bakker 4-6, 6-3, 6-4.